Detecting a "grabEnter"?

[Richard Gaskin]

Björnke von Gierke wrote:
> On 3 Sep 2008, at 17:25, Richard Gaskin wrote:
>> It's generally considered better practice to use these four handlers  
>> for  custom dragging operations:
>>
>> mouseDown -- to set a flag
>> mouseMove -- checks the flag and does the work
>> mouseUp -- clears the flag
>> mouseRelease -- also clears the flag
> 
> Yes but that method will lag much more then using grab, viewable by  
> the lone eye, while most users will never notice the huge processor  
> load when using a repeat loop. As a game oriented developer, I prefer  
> the second back draw.

If a drag is complex enough it would seem that choking the processor 
might also have an adverse effect, though I can't say I've done 
benchmarking under such circumstances; it's hard to measure things 
involving user interaction.

The demos Scott Rossi kindly put together using the four-handler method 
seem quite responsive:
<go url "http://www.tactilemedia.com/download/drag_sample.rev">

Rossi and Malte have done far more with dragging than I - you guys got 
any input on this?

Maybe even better than my earlier suggestion would be to extend the grab 
command to allow bounding arguments and callbacks, keeping the syntax 
light and the performance well optimized.

-- 
  Richard Gaskin
  Managing Editor, revJournal
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